1. Field of the Invention
This invention relates to pharmaceutical formulations having two or more pharmaceutical layers interspersed with one or more intermediate layers, wherein the pharmaceutical layers include, but are not limited to, pharmaceutical compositions useful for affecting weight loss, suppressing appetite and/or treating obesity-related conditions in individuals.
2. Description of the Related Art
Certain types of layered tablets are known in pharmaceutical applications. Some pharmaceutical applications separate potentially interacting layers from one another within a tablet. For example, U.S. Pat. No. 6,576,256 discloses separating potentially interacting compounds from each other using separate flat layers of a tablet, concentric layers, coated beads or granules, and/or using buffers. Thombre, A. G., L. E. Appel, et al. (2004), “Osmotic drug delivery using swellable-core technology” J. Control Release 94(1): 75-89 discloses a core tablet containing a drug and a water-swellable component, and one or more delivery ports in different core configurations including a tablet-in-tablet (TNT) bilayer and trilayer formation. U.S. Pat. No. 6,706,283 discloses an osmotic delivery device fabricated in a bilayer geometry, wherein the core comprises a sweller layer “sandwiched” between two drug layers. The coating of a bilayer tablet may include a water permeable membrane, but is substantially impermeable to the drug and/or the excipients contained therein. U.S. Pat. No. 6,630,165 discloses dosage forms and methods for providing sustained release reboxetine including a trilayered compressed core with a first component drug layer, a second component push layer and a third component barrier layer separating the drug layer from the push layer. The barrier layer is inert with the respect to the composition of the drug layer and substantially impermeable, such that the drug and the components of the push layer are prevented from mixing.
Among multiple layer tablet forms, one type includes a first layer to provide immediate release of a drug and a second layer to provide controlled-release of the drug. U.S. Pat. No. 6,514,531 discloses coated trilayer immediate/prolonged release tablets comprising zolpidem hemitartrate. U.S. Pat. No. 6,087,386 discloses a trilayer tablet with an enalapril layer, a losartan potassium layer and a second enalapril maleate layer or an excipient layer. U.S. Pat. No. 5,213,807 discloses an oral trilayer tablet with a core comprising a nonsteroidal anti-inflammatory drug (NSAID), ibuprofen and ibuprofen salts and an intermediate coating comprising a substantially impervious/impermeable material to the passage of ibuprofen. U.S. Pat. No. 6,926,907 discloses a trilayer tablet that separates famotidine contained in a film coat from a core comprising controlled-release naproxen formulated using excipients which control the drug release. The film coat is an enteric coating configured to delay the release of naproxen until the dosage form reaches an environment where the pH is above four.